Maximum-likelihood estimation of evolutionary trees from continuous characters.
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Alleles↗
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Results for “Continuous Evolution”
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Supporting health care workers in the treatment of HIV-infected patients.
The care of HIV-infected patients is demanding, raising concerns among health care workers regarding safety, competence, and emotional endurance. Many health care workers are reluctant to undertake this challenging work. For many professions within health care, for example nursing, there is a clearly articulated responsibility to treat all ill individuals. Less unanimity on this point continues among physicians. Clearly, a first issue is to continue the discussion of the nature of physicians' professional responsibilities and to convey an understanding of the duties of physicians to medical students and to those considering careers as doctors. Meanwhile, efforts must continue to recruit individuals in all areas of health care to work with HIV-infected people. To some extent, this process will happen as a natural consequence of the evolution of the epidemic and its decreasing geographic and demographic restriction. "Mainstreaming" AIDS care will also require continuing attention to important issues, such as acquiring and maintaining the requisite professional competence in the management of HIV-related illnesses, ensuring the availability of support services that are required for the comprehensive care of HIV complications, and continuing education on and proactive monitoring of infection control practices. All of these activities assist in the creation of a positive environment for the care of AIDS patients. In addition, the emotional consequences of caring for HIV-infected people should be directly addressed, although there is less information on which strategies are useful. A supportive working environment, characterized by some meaningful element of control by all health care workers not just the medical staff, nonauthoritarian management, explicit and responsive processes for approaching the inevitable ethical dilemmas that arise in the care of HIV-infected patients, and a recognition of the emotional, psychological, and technical aspects of medical care are essential. In such an environment, health care providers will be able to develop and institute programs that address their particular needs. Strategies that have been helpful are diverse and include support groups, rotation of clinical assignments, part-time work, social activities away from the workplace, and collective spiritual activities.
Attitude of Health Personnel↗
[Pollution level during inhalation sedation with a 50%N2O/50%O2 premix: comparison of two administration devices].
OBJECTIVES: Prefixed equimolar nitrous oxide and oxygen mixture (Kalinox) indications have risen within hospital services both as sedative and analgesic procedures. This study aimed to evaluate the levels of pollution associated with the use of two different systems of administration. STUDY DESIGN: An experimental trial was undertaken in a dental service for anxious patients or those with behavioral problems requiring nitrous oxide/ oxygen sedation for treatment. PATIENTS AND METHODS: Sedation was provided using either a continuous flow system or an on-demand system of administration of Kalinox over two consecutive periods, corresponding to 23 days of administration and 26 days without administration. The gas was administered for 122 patients in 149 procedures. The occupational exposure to nitrous oxide was measured continuously for the two evaluation periods using infrared spectrometry. The Time Weighted Average exposure (TWA) over eight hours was calculated for each system for each day with at least one sedation session. RESULTS: The mean TWA calculated for the two evolution periods was significantly lower with the on-demand system than where compared the continuous flow system (respectively 15.3 +/-23.1 and 32.3 +/-25.1 ppm; p < 0.05). CONCLUSION: The occupational exposure to nitrous oxide generated by the administration of the 50% N2O/ 50%O2 premix during dental care remained within accepted levels in relation to national recommendations for the exposed personnel.
Air Pollution, Indoor↗
Computer applications in nursing continuing education.
Until recently, computers have been synonymous with mysterious, large mainframes requiring the services of computer wizards such as programmers and system analysts. The evolution of microcomputers and the availability of commercial (off the shelf) software programs has changed this concept and has put computer capabilities and benefits within the reach of any continuing education administrator. Implementing an automated information system demands the knowledge of the administrative process, an understanding of computer devices and the software that makes them work, and training skills, particularly those related to change theory. Armed with this knowledge, one can convert a manual information system to an electronic system using a fairly inexpensive microcomputer, commercial software programs, and existing personnel.
Computer-Assisted Instruction↗
Observing development through evolutionary eyes: a practical approach.
An argument is made that only through a detailed comparison of mutational mechanisms underlying the evolution of the genetic systems governing development, can the 'logic' of individual development be fully comprehended. To do this, it is essential to choose two or more genes (or their products) that interact in the establishment of a given function, and to compare the molecular basis of that interaction in closely related species. The rationale to this approach arises from observations of molecular co-evolution between interacting partners involved with given functions which have led to species specificity in the manner in which such functions are effected. Molecular coevolution reveals that divergence in sequence can be tolerated whilst biological functions are maintained, not because it is neutral and dispensable but because successful, compensatory changes can evolve in eukaryotic genomes that are in continuous states of flux.
Animals↗
Improving continuing medical education for surgical techniques: applying the lessons learned in the first decade of minimal access surgery.
OBJECTIVE: To examine the first decade of experience with minimal access surgery, with particular attention to issues of training surgeons already in practice, and to provide a set of recommendations to improve technical training for surgeons in practice. SUMMARY BACKGROUND DATA: Concerns about the adequacy of training in new techniques for practicing surgeons began almost immediately after the introduction of laparoscopic cholecystectomy. The concern was restated throughout the following decade with seemingly little progress in addressing it. METHODS: A preliminary search of the medical literature revealed no systematic review of continuing medical education for technical skills. The search was broadened to include educational, medical, and psychological databases in four general areas: surgical training curricula, continuing medical education, learning curve, and general motor skills theory. RESULTS: The introduction and the evolution of minimal access surgery have helped to focus attention on technical skills training. The experience in the first decade has provided evidence that surgical skills training shares many characteristics with general motor skills training, thus suggesting several ways of improving continuing medical education in technical skills. CONCLUSIONS: The educational effectiveness of the short-course type of continuing medical education currently offered for training in new surgical techniques should be established, or this type of training should be abandoned. At present, short courses offer a means of introducing technical innovation, and so recommendations for improving the educational effectiveness of the short-course format are offered. These recommendations are followed by suggestions for research.
Clinical Competence↗
Evolution of the nursing process.
The nursing process, long considered the basic intellectual tool for nursing, has continued to evolve through use by advanced practice nurses (APNs). Traditionally, the nursing process has been comprehensive in guiding the assessment and intervention phases but has left unspecified the cognitive processes involved in clinical decision making. In an effort to compensate for that weakness, nurses in advanced practice have typically integrated medical diagnostic reasoning into the nursing process. The work of Benner and colleagues (1984, 1996) in explicating the unique reasoning process used by APNs has helped further our understanding of clinical decision making in advanced practice. The evolved nursing process, as described in this article, includes the array of clinical decisions that must be made during a patient encounter, including assessment decisions, diagnosis, choice of interventions, and identification of outcomes. This article reviews the nursing and medical literature related to both clinical decision making and diagnostic reasoning, and applies that literature to the evolution of the nursing process.
Decision Making↗
Timing of human immunodeficiency virus type 1 (HIV-1) transmission from mother to child: bayesian estimation using a mixture.
The timing of mother-to-child HIV transmission is not directly observable but influences the infected child's viral and immune status in the neonatal period. A hierarchical model was developed in a Bayesian framework to 'back-calculate' the timing of HIV-1 transmission from mother to child from the virological and immunological kinetics in the infected infant. Joint evolution of viral markers and immune response was modelled as a continuous time Markov process. The modelling of the period from infection to birth was based on a mixture of three distributions taking into account the various mother-to-child transmission pathways: In utero (early or late in gestation) and intrapartum (during the delivery process), integrating the fact that transmission is a continuum during the pregnancy. Gibbs sampling was used to estimate the marginal posterior distributions of the transition intensities between stages of HIV infection and those of the individual times from infection to birth. We applied our model to data on 135 perinatally HIV-1-infected children included in the French Prospective Study on Pediatric HIV infection. The model suggested that transmission occurred late in utero during the last month of pregnancy and that the day of delivery was a particularly critical time in HIV-1 transmission from mother to child. The paper ends with a discussion of model assumptions and a comparison with results obtained using a non-parametric method.
Antibodies, Viral↗
Four-way calibration applied to the simultaneous determination of folic acid and methotrexate in urine samples.
First-, second- and third-order calibration methods were investigated for the simultaneous determination of folic acid and methotrexate. The interest in the determination of these compounds is related to the fact that methotrexate inhibits the body's absorption of folic acid and prolonged treatment with methotrexate may lead to folic acid deficiency, and to the use of folic acid to cope with toxic side effects of methotrexate. Both analytes were converted into highly fluorescent compounds by oxidation with potassium permanganate, and the kinetics of the reaction was continuously monitored by recording the kinetics curves of fluorescence emission, the evolution with time of the emission spectra and the excitation-emission matrices (EEMs) of the samples at different reaction times. Direct determination of mixtures of both drugs in urine was accomplished on the basis of the evolution of the kinetics of EEMs by fluorescence measurements and four-way parallel-factor analysis (PARAFAC) or multiway partial least squares (N-PLS) chemometric calibration. The core consistency diagnostic (CORCONDIA) was employed to determine the correct number of factors in PARAFAC and the procedure converged to a choice of three factors, attributed to folic acid, methotrexate and to the sum of fluorescent species present in the urine.
Calibration↗
Predicting sampling saturation of mtDNA haplotypes: an application to an enlarged Portuguese database.
An enlarged mtDNA database ( n=549) for the Portuguese population, comprising HVRI and HVRII regions is reported. This database was used to test the effect of sample size on the estimation of relevant parameters such as haplotype diversity, number of different haplotypes, nucleotide diversity and number of polymorphic positions. Simulations were performed generating sets of random subsamples of variable sizes ( n=50, 100, 200, 300 and 400). The results show that while haplotype and nucleotide diversities do not vary significantly with sample size, the numbers of haplotypes and polymorphic positions rise continuously inside the tested interval. These trends are interpretable by the evolution of the proportions of sequences that are found once or twice, which drop dramatically as sample size increases, with the corresponding rise in the frequency of those encountered 3 times or more. The generated data were also used to extrapolate saturation curves for the referred parameters. When considering for instance the number of haplotypes, it is shown that a sample size of 1,000 individuals is required for practical saturation (defined as the point where a sample size increase of 100 individuals corresponds to an increment in the diversity measure below 5%). For HVRII the same level is reached at n=900 and n=1,300 is needed when both regions are analysed simultaneously. Consequently, we can infer that currently used sample sizes are still rather inadequate for both anthropological and forensic purposes.
DNA, Mitochondrial↗
Role of SulP, a nuclear-encoded chloroplast sulfate permease, in sulfate transport and H2 evolution in Chlamydomonas reinhardtii.
Antisense technology was applied to the green alga Chlamydomonas reinhardtiito probe the function of a novel nuclear gene encoding a chloroplast-envelope localized sulfate permease (SulP; GenBank Accession Numbers AF467891 and AF481828). Analysis showed that antiSulP transformants are impaired in sulfate uptake, a consequence of repression in the SulP gene expression. Antisense antiSulP transformants exhibited a sulfur-deprivation phenotype, strong induction of arylsulfatase activity, and global induction of sulfate assimilation gene expression. In sealed cultures, opposite to the wild-type control, antiSulP strains photo-evolved H2, underlining the notion of sulfate uptake limitation by the chloroplast, a slow-down in the rate of oxygen evolution, establishment of anaerobiosis due to internal respiration and spontaneous expression of the [Fe]-hydrogenase in these strains. It is concluded that antiSulP strains are promising as tools to limit the supply of sulfates to the chloroplast, leading to a down-regulation of H2O-oxidation and O2-evolution activity, to the constitutive expression of the [Fe]-hydrogenase and continuous H2-photoproduction in Chlamydomonas reinhardtii.Thus, antisulPstrains might permit a study of the biochemistry of H2 metabolism in this green alga under constitutive anaerobic oxygenic photosynthesis conditions.
Animals↗
Classification and nomenclature of 5-HT receptors: a comment on current issues.
Information concerning the structural, operational and transductional characteristics of 5-HT receptors continues to increase at an incredible pace, challenging our efforts to assimilate and organise it in a comprehensive manner. At the time of the Serotonin Satellite meeting in Chicago, the IUPHAR classification of receptors for 5-HT recognised four distinct receptor classes (5-HT1, 5-HT2, 5-HT3 and 5-HT4), comprising seven fully characterised functional receptor subtypes and four recombinant receptors (5-HT1D alpha, 5-HT1D beta, 5-ht1E and 5-ht1F). Four additional recombinant receptors (5-ht5A, 5-ht5B, 5-ht6 and 5-ht7) provide strong evidence for the existence three additional receptor classes. Indeed, results presented largely at the Chicago meeting have confirmed the physiological importance of both 5-ht6 and 5-ht7 receptors so that in future schemes, these will be acknowledged as fully characterised receptor classes. It is evident from this brief review that a number of issues remain to be resolved, and more are certain to follow. Some, for example the definition of the term 'physiologically relevant', as applied to recombinant receptors, will long continue to attract debate, especially between molecular biologists and pharmacologists. Others, such as the issue of species primacy, are perhaps more fundamental and can be expected to receive the urgent attention of NC-IUPHAR. These issues notwithstanding, the current scheme clearly provides a secure and rational basis for classifying and naming 5-HT receptors. The continued efforts of the SRNC are intended to encourage its further evolution towards the ultimate goal of a unitary classification for neurotransmitter/hormone receptors.
Animals↗
Georg N. Koskinas (1885-1975) and his scientific contributions to the normal and pathological anatomy of the human brain.
Georg N. Koskinas is invariably recognised by neuroanatomists as Constantin von Economo's co-author on the celebrated Die Cytoarchitektonik der Hirnrinde des erwachsenen Menschen, published 80 years ago in Vienna and Berlin. That text and Atlas are generally accepted as a monumental landmark in the evolution of morphological brain research. A number of neuroanatomists and neurophysiologists continue to use to this day the parcellation scheme of the cerebral cortex into 107 areas, proposed by von Economo and Koskinas (and logically denoted by alphabetical characters from the initials of the respective lobes), despite the commoner adoption of Brodmann's scheme of 52, randomly numbered, areas. Several works have been written about the life and work of von Economo; on the other hand, virtually nothing can be found in the biomedical literature about Koskinas. This study aims at posthumously restoring part of the fame due this illustrious man of 20th century science -- and giant figure of brain anatomy -- whom history has not treated in the fairest of ways. We present newly gathered biographical data, as well as lesser known aspects of his scientific productivity. Koskinas' neuropathological studies, in collaboration with Ernst Sträussler -- of Gerstmann-Sträussler-Scheinker disease fame -- include findings from patients inoculated with malaria as a form of therapy for progressive general paresis (research related to psychiatrist Wagner von Jauregg's 1927 Nobel Prize), colloid degeneration, and the laminar distribution of status spongiosus lesions. Koskinas' neuropsychiatric activities in Greece upon his return from Vienna in 1927, and until his parting in 1975, are further related, including his successful -- and "Hippocratic" -- practice in the suburbs of Athens, his association with the Vogt Institute for Brain Research at Neustadt, and lesser known neuroanatomical works.
Aged, 80 and over↗
Clinical information technology in hospitals: a comparison between the state of Iowa and two provinces in Canada.
Despite the growing interest in adopting information technology (IT) in healthcare, the degree of technology sophistication varies among healthcare organizations. Changes in the health care sector and continuous pressure to improve the quality of care have driven the evolution of IT in hospitals. This paper provides an overview of clinical IT sophistication in a sample of U.S. hospitals, and compares clinical IT capacities in this sample with a sample of Canadian hospitals. The instrument used for the comparison measures three clinical dimensions of IT sophistication: functional sophistication, technological sophistication and integration level. Clinical areas that were considered include patient management, patient care activities and clinical support activities. The comparison between hospitals in Iowa and Canada shows differences in clinical IT sophistication between the two settings. Hospitals in Iowa appear to have more technologies but fewer computerized processes and integration of patient management activities. Technological sophistication however, was low in both samples. Our findings confirm the construct validity of the measurement instrument and show initial evidence of its generalizability. More initiatives using the instrument would lead to enhancement in IT assessment tools that can be used for evaluation of IT in relation to patient management and quality outcomes.
Biomedical Technology↗
Relationship between the organization of the PS II super complex and the functions of the photosynthetic apparatus.
The chlorophyll fluorescence and the photosynthetic oxygen evolution (flash-induced oxygen yield patterns and oxygen bursts under continuous irradiation) were investigated in the thylakoid membranes with different stoichiometry and organization of the chlorophyll-protein complexes. Data show that the alteration in the organization of the photosystem II (PS II) super complex, i.e. the amount and the organization of the light-harvesting chlorophyll a/b protein complex (LHCII), which strongly modifies the electric properties of the membranes, influences both the energy redistribution between the two photosystems and the oxygen production reaction. The decrease of surface electric parameters (charge density and dipole moments), associated with increased degree of LHCII oligomerization, correlates with the strong reduction of the energy transfer from PS II to PSI. In the studied pea thylakoid membranes (wild types Borec, Auralia and their mutants Coeruleovireus 2/16, Costata2/133, Chlorotica XV/1422) with enhanced degree of oligomerization of LHCII was observed: (i) an increase of the S(0) populations of PS II in darkness; (ii) an increase of the misses; (iii) an alteration of the decay kinetics of the oxygen bursts under continuous irradiation. There is a strict correlation between the degree of LHCII oligomerization in the investigated pea mutants and the ratio of functionally active PS II alpha to PS II beta centers, while in thylakoid membranes without oligomeric structure of LHCII (Chlorina f2 barley mutant) the PS II alpha centers are not registered.
Chlorophyll↗
Limited Impact of Column Chemistry and Length on Proteome Coverage Under High-Speed DIA.
The evolution of mass spectrometry (MS)-based proteomics has been driven by continuous technological advances in sample preparation, liquid-phase separations, instrumentation, and data acquisition. Chromatographic performance has been recognized as a contributing factor to identification depth, particularly on earlier-generation MS platforms. Recent advances in MS sampling speed and sensitivity now raise the question of how strongly chromatographic quality continues to determine overall proteome coverage. We investigate how column chemistry and length influence proteome coverage and chromatographic selectivity under modern data-independent acquisition conditions, and whether traditional optimization priorities still apply. Spanning a matrix of experiments with five distinct stationary phases, including C18 chemistries, C8, and Phenyl-Hexyl, across eight column lengths (40-140 mm), we evaluate protein identification performance using data-independent acquisition on the Orbitrap Astral mass spectrometer. Despite differences in stationary-phase chemistry and column length, we observed remarkably convergent proteome coverage metrics. All C18 and C8 phases consistently achieved over 150,000 precursor- and approximately 9000 protein group identifications, regardless of column length variations. While retention fingerprints persisted across chemistries, these chromatographic differences did not translate into meaningful variations in proteome coverage under high-speed acquisition conditions at 200 Hz. Within the range of modern sub-2 μm reversed-phase materials tested, identification depth showed limited dependence on column chemistry and length, suggesting that for state-of-the-art stationary phases, method development priorities may increasingly favor operational robustness, throughput, and reproducibility over traditional separation optimization.
Proteome↗
Evolution of microarray analysis.
Reddy's very thorough review of the history of gene expression analysis of neurodegenerative disease made me think about the early days of microarrays, so I want to reminisce a little before commenting on the evolution of the technology and some issues that I think still continue to plague us.
Alzheimer Disease↗
Optimal management of the T1G3 bladder cancer.
TIG3 transitional cell carcinoma of the bladder represents a highly malignant tumor with a variable and unpredictable biologic potential. The most critical aspect of management requires a detailed discussion with the patient regarding the treatment options. Both the physician and the patient should be willing to reconsider the treatment options as the disease continues to evolve. In most cases initial management involves complete resection of the tumor, accurate staging of the disease, and intravesical immunotherapy or chemotherapy. Rigorous surveillance with long-term follow-up is crucial for managing these cases. In selected cases with adverse prognostic factors immediate cystectomy should be considered. The choice and timing of the decision to abandon bladder preservation and proceed with cystectomy should be continuously reconsidered on an individual patient basis, in concordance with the evolution of the disease (Fig. 1). The goal is to spare the bladder when possible but not at the risk of death from metastatic disease. Radical cystectomy in high-grade stage T1 transitional cell carcinoma offers excellent results in regard to the prevention of recurrence and progression and survival. Improvements in urinary diversion and nerve-sparing techniques have decreased the magnitude of social implications related to cystectomy in most patients regardless of gender. The discovery of reliable markers may contribute to better selection of patients for bladder sparing. Until then, the optimal treatment for the T1G3 tumor remains controversial.
Administration, Intravesical↗